The cost-effectiveness of treating women with a cervical vaginal smear diagnosis of atypical squamous cells of undetermined significance

OBJECTIVE

The purpose was to determine the optimal treatment protocol for women with a cervical vaginal diagnosis of atypical squamous cells of undetermined significance.

STUDY DESIGN

By means of decision analysis, 8 strategies were compared in terms of cost, life expectancy, cost-effectiveness, and the number of cancers and complications from treatment. Data were obtained from the medical literature and the University of Iowa Hospitals and Clinics.

RESULTS

Compared with more aggressive strategies, such as those that use immediate colposcopy, strategies featuring repeated smears were less expensive and carried fewer complications but had lower life expectancies per patient and more cancers. The strategy of repeating a smear annually had a lower cost per patient than did the other strategies, ranging from $112 to $989, and had a similar discounted life expectancy to that of the strategy with the longest discounted life expectancy.

CONCLUSIONS

In most clinical scenarios strategies that used repeated smears were the most cost-effective.

Problems encountered with the Bethesda System: the University of Iowa experience

This paper provides a descriptive summary of 1 year's experience with the Bethesda Cytologic Classification System at the University of Iowa Hospitals and Clinics. Cytotechnologists and pathologists criticized the failure of the new classification system to provide microscopic criteria for the following categories: adequacy of the smear (satisfactory, less than optimal, unsatisfactory), atypical squamous cells of undetermined significance, atypical glandular cells of undetermined significance, and inflammation-associated changes. Clinicians criticized the "less than optimal" category and the reporting of koilocytosis, moderate dysplasia, and endometrial cells. Suggestions for modifying the Bethesda System include: eliminating the less than optimal response, defining what constitutes an unsatisfactory smear, eliminating the terms low-grade and high-grade squamous intraepithelial lesion, and changing the reporting of endometrial cells.

The second-messenger system for peptide hormones

There are three major hormone classes--peptide, steroid, and the newly defined growth factors--each with its own system for signal transduction in the cell. Two interdependent theses are proposed for the peptide hormone: that incoming signal transduction requires coupling to a G protein in a second-messenger pathway, and that second-messenger redundancy assures checks and balances in cell regulation.

Immunolocalization of ornithine decarboxylase in rat heart atria

Mammalian atrial myocytes secrete a potent natriuretic and diuretic factor, atrial natriuretic peptide (ANP), in response to volume expansion or elevations of right atrial pressure. ANP is synthesized in the atrial atrial myocytes and stored in cytoplasmic secretory granules. Ornithine decarboxylase (ODC) is the initial rate-limiting enzyme in the biosynthesis of polyamines, organic cations which are essential for various aspects of DNA, RNA and protein synthesis, structure, and function. The enzyme has been reported to be localized predominantly in the cytoplasm. A polyclonal antibody elicited against ODC was used to analyse the intracellular distribution of the enzyme protein within atrial myocytes at the ultrastructural level through the use of a post-embedding immunogold technique. In control animals, the density of gold particles associated with the atrial granules was seven to 30-fold higher than that detected in association with other subcellular structures. Administration of Isoproterenol increased atrial of Isoproterenol increased atrial ODC activity 18-fold and the density of the immunolabelling of the atrial myocytes five-fold. Statistically significant increases in the density of labelling after stimulation occurred in association with the atrial granules and the nucleus. After isoproterenol stimulation, 60% of the immunodetectable ODC protein in the atrial myocyte was found in association with the atrial granules. The atrial granules were demonstrated to contain ANP by immunocytochemical analysis of adjacent sections.

Increase in liver protein phosphatase-1 in spontaneously diabetic Chinese hamsters

Two broad-specifically protein phosphatases, termed protein phosphatase-1 (PrP-1) and protein phosphatase-2A (PrP-2A), accounting for all the hepatic activity regulating glycogen phosphorylase, were measured in spontaneously diabetic Chinese hamsters exhibiting persistent glycosuria. When compared with genetically related inbred sublines free of glycosuria, diabetic animals demonstrated approximately 25% increase in PrP-1 activity measured either in crude tissue extracts or in cytosols fractionated by ion-exchange chromatography. No significant alteration in total PrP-2A activity was observed in the diabetic animals. These findings indicate that a specific change in hepatic PrP-1 is associated with genetically acquired diabetes in Chinese hamsters. In contrast to reported data using animals with experimentally induced diabetes mellitus, hepatic PrP-1 was increased in the spontaneously diabetic Chinese hamsters. The data suggests that distinct alterations in PrP-1 and associated metabolic consequences are exhibited by different types of diabetes.

A new technique for removal of amorphous phase tissue water without ice crystal damage: a preparative method for ultrastructural analysis and immunoelectron microscopy

An apparatus has been produced that can remove amorphous phase tissue water via molecular distillation without devitrification or rehydration. This method represents a fundamental advance in tissue preparation, making possible for the first time ultrastructural localization of soluble molecular entities without the problems of alteration, re-distribution, and loss which have plagued conventional techniques. Fresh slices of rat brain, liver, or kidney, and monkey retinal tissue were cryofixed by bounce-free, metal mirror cooling on copper bars immersed in liquid nitrogen (LN2). Tissue transferred under LN2 was then placed in a precooled copper specimen block, which was subsequently lowered into a LN2-cooled stainless steel chamber. After rough pumping at 1 X 10(-3) mbar with a mechanical pump to remove LN2, the chamber was evacuated with a cryopump or turbomolecular pump to achieve a hydrocarbon-free, ultra-high vacuum of 1 X 10(-8) mbar. Equilibrium temperature in the chamber before the drying cycle was -192 degrees C. The copper specimen block was equipped with a thermocouple and a programmable feedback-controlled heating circuit. Tissue was dried by increasing the specimen block temperature 1 degree C/hr during the critical drying phase while monitoring the rate of water removal with a partial pressure analyzer. Results obtained indicate that drying is complete below the devitrification temperature of amorphous phase tissue water. Dried tissue was fixed with osmium tetroxide vapor, vacuum-embedded in a low-viscosity epoxy resin, sectioned, stained, and viewed with the electron microscope. Processed tissue exhibits excellent morphological preservation without the use of pre-fixation or cryoprotective agents. Thin sections of this tissue are excellent for immunocytochemical staining and electron microprobe analysis.

Effect of retinoic acid on cellular content and human parathyroid hormone activation of cyclic adenosine 3':5'-monophosphate-dependent protein kinase isoenzymes in clonal rat osteogenic sarcoma cells

Pretreatment with 10(-8) M retinoic acid for 4 days caused changes in three distinct components of the parathyroid hormone (PTH)-stimulated cyclic adenosine 3':5'-monophosphate response in a clonal rat osteogenic sarcoma cell line, UMR 106-06: the amplitude of the cyclic adenosine 3':5'-monophosphate response to PTH was moderately increased after pretreatment with retinoic acid; while the cellular content of the two isoenzymes of the cyclic adenosine 3':5'-monophosphate-dependent protein kinase was approximately equal in control cells, retinoic acid pretreatment was associated with a marked increase in the ratio of type II to type I holoenzyme activity. This change might be due to a decrease in the type I holoenzyme as suggested by immunofluorescence detection of decreased type I regulatory subunit in fixed cells together with the relative decrease in type I holoenzyme determined biochemically; there was a marked alteration of the pattern of PTH-stimulated protein kinase isoenzyme activation from predominantly type I isoenzyme in control cells to almost exclusively type II isoenzyme in retinoic acid-treated cells. Growth inhibition by submaximal amounts of PTH and retinoic acid when added together was greater than that for either agent alone.

Characterization of cyclic AMP-binding proteins in rat sertoli cells using a photoaffinity ligand

Protein-bound cyclic AMP (cAMP) levels in cultured rat Sertoli cells have been determined after exposure to follicle-stimulating hormone (FSH) and agents which elevate intracellular cAMP or mimic cAMP action. Changes in the content of protein-bound cAMP were correlated with changes in receptor availability determined by measuring [3H] cAMP binding. Using the photoaffinity analog of cAMP, 8-N3 [32P] cAMP, two major cAMP-binding proteins in Sertoli cell cytosol, with molecular weights of 47 000 and 53 000 daltons, were identified as regulatory subunits of type I and type II cAMP-dependent protein kinases, respectively. Densitometric analysis of autoradiograms demonstrated differential activation of the two isozymes in response to treatment with FSH and other agents. Results of this study demonstrate the value of measuring changes in protein-bound cAMP and the utility of the photoaffinity labeling technique in correlating hormone-dependent processes in which activation of cAMP-dependent protein kinase occurs.

Immunocytochemical localization of cyclic GMP, cGMP-dependent protein kinase, calmodulin and calcineurin in Paramecium tetraurelia

The localization of cGMP, cGMP-dependent protein kinase, calmodulin and the calmodulin-binding protein calcineurin in Paramecium tetrauelia cells has been examined with immunocytochemical methods. These molecules appeared to be localized to a large extent in the cilia of this protozoan. To ascertain that antibodies had access to all cellular compartments we have used three different preparations for immunocytochemistry: (i) with 'whole cell' preparations immunofluorescent staining for the four molecules was mainly visible in the cilia; (ii) in 'deciliated' Paramecium, staining for cGMP and calmodulin was found in regular patterns on the cell surface most likely representing kinetosomes; (iii) using 'sectioned cells', additional cytoplasmic calmodulin appeared to be associated with glycogen particles as evidenced by the disappearance of the granular staining pattern after preincubation with alpha-amylase. In contrast, cGMP, cGMP-dependent protein kinase and calcineurin fluorescence was only very weak and diffuse in cell bodies. No nuclear fluorescence was detectable after staining with any of the antibodies. Because of the colocalization of cGMP, cGMP-dependent protein kinase, a guanylate cyclase-calmodulin-complex, and calcineurin in cilia from Paramecium, an involvement of these components in the regulation of ciliary activity is discussed.

Immunofluorescent localization of cGMP, cGMP-dependent protein kinase, calmodulin and cAMP in the rat uterus. Effects of estrogen treatment

Cyclic guanosine 3',5' monophosphate (cGMP), cGMP-dependent protein kinase, calmodulin and cyclic adenosine 3',5' monophosphate (cAMP) were localized in the uterus of the immature rat by an indirect immunofluorescence technique. cGMP, cGMP-dependent protein kinase and calmodulin were detected predominantly along epithelial and myometrial plasma membranes and in the adjacent cytoplasm. In contrast, cAMP immunoreactive material was found principally in the cytoplasm of connective tissue. After administration of 17 beta-estradiol, similar time-dependent changes were observed in the localization of cGMP, cGMP-dependent protein kinase and calmodulin in all uterine cell types. For the three compounds, nucleolar-like distribution of the immunofluorescence appeared approximately 12 h after treatment. A more dispersed, reticular distribution of the nuclear fluorescent staining was observed 20-24 h after hormonal treatment. Estrogen did not affect the localization of cAMP. The simultaneous mobilization of cGMP, cGMP-dependent protein kinase and calmodulin towards the same nuclear loci suggests concerted roles for these three molecules in nuclear metabolic processes during the development of the uterotrophic action of estrogens.

Methods of cervical priming

It is now well recognized that a priming agent without untoward effects on mother or fetus is highly desirable when an indicated induction is required in the face of an unripe cervix. There appears to be a potential role for Laminaria, estrogens, relaxin, and various forms and routes of administration of prostaglandins because efficacy has been reported with all of these methods. With careful selection of patients and judicious fetal monitoring, there are multiple reasonable modes available, although an ideal priming agent has not yet emerged.

Follicle-stimulating hormone-dependent phosphorylation of vimentin in cultures of rat Sertoli cells

Endogenous protein phosphorylation was investigated in cultured rat Sertoli cells after treatment with follicle-stimulating hormone (FSH) and pharmacological agents that activate cAMP-dependent protein kinases. In intact Sertoli cells, both phosphorylation and dephosphorylation of proteins occurred in response to treatment with these agents. Studies using cell-free preparations suggest that four phosphoproteins phosphorylated by cAMP or the catalytic subunit of cAMP-dependent protein kinase were also phosphorylated in a FSH-dependent manner in intact cells. These data suggest that FSH-dependent phosphorylation in Sertoli cells occurs through activation of a cAMP-dependent protein kinase. A FSH-dependent phosphoprotein with a molecular weight of 58,000 was identified as the intermediate filament protein vimentin, based on its migration in two-dimensional gels and its peptide map. The cellular distribution of vimentin was monitored by immunofluorescence in Sertoli cells after treatment with FSH. Results of this study support a role for intermediate filaments in FSH-dependent events in Sertoli cells.

Localization of the catalytic subunit of cyclic AMP-dependent. Protein kinase in cultured cells using a specific antibody

We developed a specific antibody to the catalytic subunit (C-subunit) of cyclic AMP-dependent protein kinase and used it to localize C-subunit in cultured cells. C-subunit antigen was purified from bovine cardiac muscle and cross-linked to hemocyanin with glutaraldehyde. Immunized goat serum showed a low titer of antibody after boosting; it was enriched 100-fold by affinity chromatography on catalytic subunit-Sepharose. The antibody immunoprecipitated C-subunit from type I and type II holoenzyme and depleted enzymatic activity from solution. At 12.5 nM antigen, 1 microgram antibody immunoprecipitated 10 ng of C-subunit. Immunoprecipitation of 35S-labeled cell extracts and 125I-antibody detection on nitrocellulose paper revealed that the antibody specifically reacts with C-subunit in Chinese hamster ovary (CHO) whole cell extracts. Using indirect immunofluorescence to localize C-subunit, we found a pattern of diffuse staining in the cytoplasm of CHO cells with little or no nuclear staining. A similar distribution of the enzyme was observed in Swiss 3T3 cells, bovine endothelial tracheal cells, human lung fibroblasts and NRK cells. Treatment of CHO cells with 8-bromo-cyclic AMP produced no change in the pattern or intensity of immunofluorescence. We conclude that the majority of C-subunit is localized in cytoplasm and that in cultured fibroblasts exposure to cyclic AMP analogues causes no apparent redistribution of catalytic subunit.

Post-natal ontogenesis of calmodulin and cyclic AMP-dependent protein kinase subunits in the Purkinje cell using immunofluorescence

Specific immunofluorescent techniques were utilized to demonstrate the regulatory (RI and RII) and catalytic (C) subunits of cyclic AMP-dependent protein kinase, and calmodulin, in the rat cerebellar Purkinje cell during post-natal ontogenesis. Whereas these second messenger receptor proteins were not detectable at 5 days, an increase in staining intensity occurred from this time until adult levels and distribution were attained at 25 days. Differences in immunofluorescent staining were noted between these proteins during ontogenesis. The relationship of these immunocytochemical changes to synaptogenesis and cellular maturation are discussed, including possible interactions between cyclic AMP and calcium messenger systems.

Hormonal effects on the immunocytochemical location of 3',5'-cyclic adenosine monophosphate-dependent protein kinase in rat tissues

Homogeneous preparations of type I and type II regulatory subunits (RI and RII, respectively) of cAMP-dependent protein kinase (cAMP kinase) were utilized as antigens to obtain isozyme specific antisera. Injections of pure catalytic subunit (C) from the type I isozyme resulted in antisera that reacted with C subunit obtained from either isozyme type. Cross-reactivity of the antisera raised against isolated subunits of the kinase was assessed by immunodiffusion analysis and by measuring the cAMP binding and phosphotransferase activities of the subunits after immunoprecipitation. These antisera were used to localize subunits of type I and type II cAMP kinases in rat skeletal muscle, liver, and adrenal by using indirect immunofluorescence and immunoperoxidase techniques. Specificity of the immunofluorescence was shown by absorption of the antisera with pure homologous antigens. In skeletal muscle, both R and C subunits of the type I and type II cAMP kinases were localized in the area of the sarcoplasmic reticulum and in periodic crossbands. Specific fluorescence for these components was observed in both isotropic and anisotropic band regions of the sarcomere. Densitometric determinations of immunoperoxidase staining revealed a larger amount of RI, RII, and C subunits in the isotropic band than in the anisotropic band regions. In liver, C, RI, and RII subunits were distributed both in cytoplasmic and nuclear areas and along plasma membranes of hepatocytes; however, there were qualitative differences observed among these various subcellular sites. With each antiserum, fluorescence was blocked by prior absorption with homologous antigen. After treatment of rats with glucagon, dramatic changes in the relative distribution patterns of C and RII were noted in the nucleus. In the adrenal gland, RI, RII, and C subunits were localized in both cytoplasmic and nuclear areas, and an apparent redistribution of these subunits occurred after treatment of (dexamethasone-suppressed) rats with ACTH. The application of this immunocytochemical approach provides a tool for examining and monitoring the subcellular distribution of these components of cAMP kinase in biological systems.

Immunocytochemical localization of cyclic guanosine monophosphate-dependent protein kinase in endocrine tissues

Antisera have been produced against purified soluble cyclic guanosine monophosphate (cGMP) dependent-protein kinase (ATP: protein phosphotransferase EC 2.7.1.37) isolated from bovine lung. No cross-reactivity was observed between the antisera and structurally related components of cAMP-dependent protein kinases (cAMP kinase), as judged by the immunodiffusion and immunoprecipitation techniques. Immunocytochemical specificity was determined by absorption of antisera with pure antigen. The distribution of cGMP kinase has been examined in several rat tissues, using an indirect immunofluorescence technique, and compared with the immunocytochemical distribution of cGMP. In skeletal muscle, cGMP kinase was localized primarily to A bands on the muscle fiber and along the Z line in I band regions. Densitometric determinations of immunoperoxidase staining indicated that absorbance over A band areas was greater than absorbance over the I band regions. In small intestine, cGMP kinase is distributed primarily along the villus brush border membrane. In testis, cGMP kinase is observed in several cell types adjacent to the seminiferous tubular wall, including Sertoli cells and spermatogonia, as well as in association with meiotic chromosomes of pachytene spermatocytes. In the cortex of the adrenal glands from dexamethasone-suppressed rats, chronic ACTH treatment induced an increase in cGMP kinase fluorescence in nuclei. In each of the tissues examined, a striking correlation was observed between the distribution of cGMP kinase and cGMP, supporting the hypothesis that cGMP-mediated actions occur via cGMP kinases.

Immunofluorescent localization of cyclic GMP, calmodulin and cyclic GMP-dependent protein kinase in the choroid plexus

An immunofluorescent technique has demonstrated that tissue-bound pools of cyclic GMP, calmodulin and cyclic GMP-dependent protein kinase are localized within the cytoplasm of the epithelial cells of the choroid plexus. In all other cell types and regions of the central nervous system previously examined, however, these molecules have shown contrasting immunofluorescent localization. These results suggest that the interaction in the choroid plexus may be related to the specialized physiological functions of the neuroglial epithelial cell.

Compartmentalization of cyclic AMP during phagocytosis by human neutrophilic granulocytes

Immunocytochemistry shows that early during phagocytosis of zymosan, adenosine 3',5'-monophosphate (cyclic AMP) appears on the cell surface before the phagosome is internalized. The appearance of cyclic AMP on the cell surface is coincident with that of granule products and regulatory subunit of type I cyclic AMP-dependent protein kinase. Guanosine 3',5'-monophosphate is not associated with the initiation site of phagocytosis, but is observed throughout the granular cytoplasmic region. This sharply localized accumulation of cyclic AMP may serve as a signal for the initiation of phagocytosis.

Immunofluorescent localization of cyclic nucleotide-dependent protein kinases on the mitotic apparatus of cultured cells

Cyclic nucleotides and cyclic nucleotide-dependent protein kinases have been implicated in the regulation of cell motility and division, processes that depend on the cell cytoskeleton. To determine whether cyclic nucleotides or their kinases are physically associated with the cytoskeleton during cell division, fluorescently labeled antibodies directed against cyclic AMP, cyclic GMP, and the cyclic nucleotide-dpendent protein kinases were used to localize these molecules in mitotic PtK1 cells. Both the cyclic GMP-dependent protein kinase and the type II regulatory subunit of the cyclic AMP-dependent protein kinase were localized on the mitotic spindle. Throughout mitosis, their distribution closely resembled that of tubulin. Antibodies to cyclic AMP, cyclic GMP, and the type I regulatory and catalytic subunits of the cyclic AMP-dependent protein kinase did not label the mitotic apparatus. The association between specific components of the cyclic neucleotide system and the mitotic spindle suggests that cyclic nucleotide-dependent phosphorylation of spindle proteins, such as those of microtubules, may play a fundamental role in the regulation of spindle assembly and chromosome motion.

Immunohistochemical localization of cyclic AMP, cyclic GMP and calmodulin in Dictyostelium discoideum

Using an indirect immunofluorescence technique cyclic AMP, cyclic GMP and calmodulin have been localized in Dictyostelium discoideum cells. The bound cyclic AMP is localized throughout the cell. Cyclic GMP and calmodulin are markedly localized in the nuclear area of the cell. No changes in the pattern of staining was observed during differentiation. Chemotactic stimulation induced a transient increase of cyclic GMP staining.

Localization of calmodulin in rat tissues

The localization of calmodulin, a calcium-dependent modulator of many enzymes, was studied in rat liver, skeletal muscle, and adrenal slices. Calmodulin is found in liver cytoplasm, nucleus, and plasma membrane. Much of the cytoplasmic calmodulin is associated with glycogen particles presumably bound to enzymes involved in glycogen metabolism. Skeletal muscle calmodulin is found on the I-band, also associated with glycogen particles. Intermyofibrillar staining that is not glycogen associated is also observed. Calmodulin is localized in the cytoplasm and nucleus of adrenal cortex cells. Injection of corticotropin leads to a greatly increased localization of calmodulin in nuclei of the adrenal cortex. These observations suggest that one role of calmodulin may be the regulation of hormone effects on nuclear processes.

Characterization of rat testicular guanylate cyclase during development

The biochemical characteristics of rat testicular guanylate cyclase were investigated and the activity and subcellular distribution of the enzyme was determined during testicular development. Examination of the effects of metal ions, nucleotides, detergents and other in vitro activators on the activity of guanylate cyclase revealed that the testicular enzyme is similar in most respects to guanylate cyclase isolated from other mammalian tissues. Changes in the total activity of guanylate cyclase during testicular development paralleled changes in the tissue concentration of cyclic GMP; i.e. guanylate cyclase activity and tissue cyclic GMP were highest during the early stages of development. Subcellular fractionation revealed that the activity of the soluble form of guanylate cyclase was best correlated with tissue cyclic GMP. Biochemical analysis of the soluble enzyme prepared from testes of neonatal and adult rats did not reveal any significant differences in the characteristics of the enzyme during ontogeny with the exception of a 2.5 fold increase in V noted in the neonatal testis. The results of this study are consistent with a molecular mechanism that allows independent regulation of the different forms of guanylate cyclase.

Digger wasp predatory behavior (Hymenoptera, Sphecidae): fly hunting and capture by Oxybelus uniglumis (Crabroninae: Oxybelini); a case of extremely concentrated stinging pattern and prey nervous system

Several Orthoptera-hunting wasps usually deliver four paralyzing stings to their prey (one for each thoracic segment and one for the ventral side of the neck) in a predictable, although not immutable, order. This also matches the number of thoracic ganglia of the ventral nerve cord and leg pairs plus the subesophageal ganglion that controls the potentially dangerous mandibles. Oxybelus wasps usually deliver only one thoracic sting, behind one foreleg base, and no neck sting. Many flies have only a single mass of fused ganglia in the thorax, no subesophageal ganglion, and no potentially dangerous mouthparts. Furthermore, some Oxybelus wasps use the sting for prey carriage. The number of thoracic stings matches the number of thoracic ganglionic masses (one), rather than the number of leg pairs (three), thoracic segments (three), or pairs of easily punctured soft membranes (three). This case of extremely reduced paralyzing sequence and prey nervous system is discussed from an evolutionary standpoint and compared with cases in which less or no such reduction occurred. Correlative differences in the state of the prey are also considered.

Particulate guanylate cyclase of skeletal muscle: effects of Ca2+ and other divalent cations on enzyme activity

The properties of particulate guanylate cyclase (GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2) from purified rabbit skeletal muscle membrane fragments were studied. Four membrane fractions were prepared by sucrose gradient centrifugation and the fractions characterized by analysis of marker enzymes. Guanylate cyclase activity was highest in the fraction possessing enzymatic properties typical of sarcolemma, while fractions enriched with sarcoplasmic reticulum had lower activities. In the presence of suboptimal Mn2+ concentrations, Mg2+ stimulated particulate guanylate cyclase activity both before and after solubilization in 1% Triton X-100. Guanylate cyclase activity was biphasic in the presence of Ca2+. Increasing the Ca2+ concentration from 10(-8) to 10(-5) M decreased the specific activity. As the Ca2+ concentration was further increased to 5 . 10(-4) M enzyme activity again increased. After solubilization of the membranes in 1% Triton X-100, Ca2+ suppressed enzyme activity. Studies utilizing ionophore X537A indicated that the altered effect of Ca2+ upon the solubilized membranes was independent of asymmetric distribution of Ca2+ and Mg2+.

Tissue guanosine-3',5'-cyclic monophosphate levels and soluble guanylate cyclase activity: a positive correlation during unilateral cryptorchidism in the rat testis

The relationship between the subcellular distribution of guanylate cyclase and tissue guanosine-3',5'-cyclic monophosphate (cGMP) levels was investigated in rat testes after surgically induced unilateral cryptorchidism. Placement of one of a testis pair in the abdominal cavity results in loss of testicular weight and function in the abdominal testis whereas the remaining scrotal testis appears to be functionally normal. Within 5 days after surgery, tissue cGMP levels were increased by twofold in the abdominal testis. A fourfold elevation was noted from 10 to 30 days after surgery. Whereas the homogenate guanylate cyclase activity was only slightly elevated 10 and 20 days postoperatively, a 200% increase in the soluble guanylate cyclase activity was seen at 5 days. Between 10 and 30 days, the rise in activity was >250% (P < 0.01). An increase in soluble guanylate cyclase activity was noted when the data were expressed as per milligram protein, per milligram DNA or per whole testis. Conversely, particulate guanylate cyclase activity was reduced by 40% in the cryptorchid testis. Kinetic analysis of the soluble enzyme prepared from abdominal and scrotal testes yielded linear Line-weaver-Burke plots for both enzyme preparations with an identical K(m) for guanosine triphosphate, but a three-fold higher maximal velocity for the abdominal enzyme. When the soluble guanylate cyclases from both testes were mixed and assayed together, the activities were additive rather than exhibiting synergism or inhibition. These experiments indicate that the altered V(max) is not due to a transferable activator or inhibitor.An immunocytochemical technique was used to assess the cell type in which the alterations in cGMP metabolism occurred. Comparison of the scrotal and abdominal testes revealed that the abdominal testis exhibited enhanced cGMP immunofluorescence within the cells lining the inner aspect of the seminiferous tubule as well as tubular elements and interstitial cells. Thus, it is inferred that the correlated changes in soluble guanylate cyclase activity and cGMP levels occur in several of the cell types that remain viable within the cryptorchid testis.

Association of cyclic GMP with gene expression of polytene chromosomes of Drosophila melanogaster

The distribution of cyclic nucleotides on polytene chromosomes isolated from Drosophilia melanogaster salivary glands was examined by using an indirect immunofluorescent technique. With a fixative that minimized the loss of chromosomal proteins, cyclic GMP, but not cyclic AMP, was observed distributed along the chromosomes. The subchromosomal distribution of cyclic GMP correlated with genetically active sites on the chromosomes. After heat-shock treatments, the intensity of cyclic GMP fluorescence was markedly enhanced at specific loci on the chromosomes, with locus 93D as the most intensely fluorescent. Autoradiographic analysis with [3H]uridine revealed that 93D was the most transcriptionally active locus within a particular nucleus. These observations suggest that cyclic GMP may participate in processes associated with transcription on polytene chromosomes. The involvement of cyclic GMP in nuclear events associated with gene expression is discussed.

Immunohistochemical localization of 3':5'-cyclic AMP and 3':5'-cyclic GMP in rat renal cortex: effect of parathyroid hormone

Adenosine 3':5'-cyclic monophosphate (cAMP) and guanosine 3':5'-cyclic monophosphate (cGMP) were localized in cells of rat kidney cortex by an immunocytochemical technique before and after perfusion with parathyroid hormone (PTH). In control tissues the cAMP antiserum detected approximately the same intensity of fluorescence in cytoplasmic epithelial cell elements of cortical tubules and glomeruli (cells of Bowman's capsule and podocytes). PTH increased fluorescence in these glomerular cells and increased cAMP fluorescence in cytoplasmic granules in proximal tubular cells. These granules, whose structure has not been identified, were located predominantly on the luminal side of the tubular cells. In control rats, the renal cortical fluorescence detected with the cGMP antiserum was more pronounced in glomeruli (predominantly in the mesangial areas) and lesser amounts of fluorescence were observed in tubules. After PTH treatment, cGMP fluorescence increased in glomeruli and in renal tubular cells. A bright linear pattern of fluorescence was found in the area of the tubular luminal membrane. Perfusion with PTH caused relatively small increases in total tissue cAMP and no consistent increases in total tissue cGMP. Our observations suggest that both cAMP and cGMP are involved in the glomerular and tubular responses to PTH and point out the added dimension that this immunocytochemical technique brings to studies of cyclic nucleotide dynamics in heterogeneous tissues.

Lymphocyte surface modulation and cyclic nucleotides I. Topographic correlation of cyclic adenosine 3':5'-monophosphate and immunoglobulin immunofluorescence during lymphocyte capping

The cross-linking of human peripheral lymphocyte surface Ig results in an early association of cyclic adenosine 3':5'-monophosphate (cAMP) and the cell surface Ig patches. Examination of the subsequent stages of cap formation reveals the continued relationship of cAMP and the clustered surface Ig. In addition, the generalized influx of calcium produced by the ionophore A-23187 disrupts human lymphocyte caps. During the process of cap dissolution cAMP is still associated with surface Ig. Therefore, it is hypothesized that the localized concentration of cyclic nucleotide and calcium ion regulates the movement of cell surface constituents by coordinating the function of the cell's contractile and structural elements.

Regulation of hepatic nuclear guanylate cyclase

In immunohistochemical studies of rat liver tissue slices and purified nuclei, adenosine 3':5'-cyclic monophosphate (cAMP) and guanosine 3':5'-cyclic monophosphate (cGMP) immunofluorescence on the nuclear membrane are sequentially increased after glucagon administration. An explanation for the increased cGMP immunofluorescence was sought in experiments in which guanylate cyclase [GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2]activity of hepatic subcellular fractions was determined. The results showed that a nuclear guanylate cyclase exists which can be distinguished from the soluble and crude particulate guanylate cyclases. The activity of the nuclear enzyme was increased by 35% in nuclei isolated from rats 30 min after glucagon injection, the time at which maximal nuclear membrane cGMP immunofluorescence is observed. Because glucagon altered both cAMP location and levels prior to the observed changes in nuclear cGMP metabolism, the hypothesis that cAMP acted as the second messenger was tested. In vitro incubation of nuclei isolated from control rats with 10(-5) M cAMP produced a 25% increase in nuclear guanylate cyclase activity. With nuclei isolated from glucagon-treated rats, no significant increase in enzyme activity was observed; this indicates that maximal stimulation of nuclear guanylate cyclase by cAMP occurred at levels that are obtained in vivo after glucagon administration. These findings suggest that hepatic nuclear cGMP content may be regulated by a specific organelle guanylate cyclase and that cAMP may be one of the determinants of this enzyme's activity.

Localization of cyclic GMP and cyclic AMP in cardiac and skeletal muscle: immunocytochemical demonstration

When rat cardiac and skeletal muscle are explored by immunocytochemical procedures designed to show sites of localization of adenosine 3',5'-monophosphate (cyclic AMP) and guanosine 3',5'-monophosphate (cyclic GMP), distinct staining patterns for the two nucleotides are seen. Antibody to cyclic AMP is found in the area of the sarcoplasmic reticulum, while antibody to cyclic GMP is found with a periodic distribution corresponding to that of the A band. This suggests a role for cyclic GMP in the regulation of myosin.

Cyclic nucleotides in pancreatic islets. Tolbutamide- and arginine-induced insulin release

With the use of isolated rat islet perfusion, levels of the islet cyclic adenosine 3' ,5' -monophosphate (cAMP) were compared with dynamic insulin secretion induced by tolbutamide and arginine. Tolbutamide elevated islet cAMP rapidly and augmented both glucose-induced islet cAMP levels and insulin secretion; arginine, however, did not elevate islet cAMP but did enhance glucose-induced insulin secretion. Since the latter result could have been modulated by cyclic guanosine 3' ,5' -monophosphate, this cyclic nucleotide was also measured and found to remain unchanged during stimulation of insulin secretion by arginine and a combination or arginine and glucose. Thus, the action of tolbutamide appears to be modulated in part by cAMP, whereas arginine appears to augment insulin secretion independently of cyclic nucleotides.

Effect of angiotensin II on cyclic guanosine monophosphate and cyclic adenosine monophosphate in human plasma

Infusion of alpha-adrenergic catecholamines increases plasma cyclic guanosine monophosphate (pcGMP), raising the possibility that the pressor effect of these agents may be mediated by cyclic GMP. We infused pressor doses of angiotensin II in 10 studies in 8 normal subject and measured pcGMP and plasma cyclic adenosine monophosphate (pcAMP) by radioimmunoassay. After 120 minutes of infusion, mean pcGMP was 128 +/- 31% (SE) higher than baseline values (P less than 0.01) while pcAMP was increased 30 +/- 10% (P less than 0.05).

Neurotransmitters increase cyclic nucleotides in postganglionic neurons: immunocytochemical demonstration

Dopamine increases adenosine 3',5'-monophosphate (cyclic AMP) but not guanosine 3',5'-monophosphate (cyclic GMP) in slices of bovine sympathetic ganglion; this increase is localized to the postganglionic neurons. Conversely, acetylcholine increases cyclic GMP but not cycle AMP in the ganglion; this increase also occurs within postganglionic neurons. Thus, different neurotransmitters can selectively alter cyclic nucleotide levels within the same neuronal population.

Control and localization of rat adrenal cyclic guanosine 3', 5'-monophosphate. Comparison with adrenal cyclic adenosine 3', 5'-monophosphate

Cyclic AMP and cyclic GMP were measured in rat adrenal glands after either hypophysectomy alone or after hypophysectomy and treatment with ACTH. Adrenal cyclic GMP levels rise in acutely hypophysectomized rats to a maximum at 1 h of approximately 200% of control levels; there is a return to base line at 4-12 h after hypophysectomy. In contrast, adrenal cyclic AMP falls immediately to about 50% of control levels after hypophysectomy and remains at approximately 1 pmol per mg tissue. Doses of ACTH beyond the physiological range markedly suppress adrenal cyclic GMP while producing a 50-fold or greater rise in cyclic AMP in hypophysectomized rats. This pattern of adrenal cyclic GMP rise was unchanged in acutely hypophysectomized animals treated with desamethasone. N-6-2'-0 dibutyryl cyclic AMP acted similarly to the effect of ACTH in bringing about a suppression of adrenal cyclic GMP levels. Physiological i.v. pulse doses of ACTH produced a rapid dose related increase in adrenal cyclic GMP. In vitro incubation of quartered adrenal pairs with 500 mU ACTH produced elevated cyclic AMP levels and suppression of cyclic GMP. Whereas adrenal cyclic AMP fell rapidly to 50% of control levels after hypophysectomy and remained at about 1 pmol per mg tissue for 7 days, adrenal cyclic GMP showed a biphasic rhythm in long-term hypophysectomized animals. After an initial peak at 1 h after hypophysectomy, adrenal cyclic GMP declined to baseline at 4-12 h but thereafter progressively rose with time, eventually reaching levels over 1 pmol per mg tissue. Fluorescent immunocytochemical staining of rat adrenal zona fasciculata showed cyclic AMP largely confined to cytoplasmic elements with little fluorescence contained in nuclei. In constant, cyclic GMP was found discretely positioned in nuclei with prominent fluorescence in nucleoli in addition to cytoplasmic localization. It is concluded that in hypophysectomized rats ACTH, either directly or in conjunction with altertion of adrenal cyclic AMP, appears to be one factor which regulates adrenal cyclic GMP. The direction of cyclic GMP change and the different subcellular localization of the nucleotides suggest divergent roles for cyclic AMP and cyclic GMP in adrenocortical function. Furthermore, our observations suggest a role for adrenal cyclic GMP in nuclear directed events.

Immunohistochemical localization of 3': 5'-cyclic AMP and 3': 5'-cyclic GMP in rat liver, intestine, and testis

Cyclic GMP and cyclic AMP have been localized in rat liver, small intestine, and testis by a fluorescent immunocytochemical procedure. In liver, cyclic AMP is distributed along sinusoids predominantly, and increased fluorescence is seen sinusoidal areas after glucagon administration. Cyclic GMP is located in nuclear elements and on the plasma membranes of hepatocytes. In jejunum, cyclic AMP is found predominantly at the basal and lateral sides of brush border cells and in the lamina propria, while cyclic GMP is located to the brush border membrane, smooth muscle, and nuclear elements. In testis, cyclic AMP is found in cytoplasm of cells at the perimeter of the seminiferrous tubules and in interstitial cells, while cyclic AMP is visualized on the plasma membrane of the cells lining the tubules. Cyclic GMP is also seen on chromosomes of premeiotic spermatocytes and in sperm. These data provide histological evidence implicating diverse roles for the nucleotides in these tissues. The nuclear localization of cyclic GMP in all of these tissues suggests a role for the nucleotide in nucleus-directed events.

Muscarinic cholinergic regulation of cyclic guanosine 3,5-monophosphate in autonomic ganglia: possible role in synaptic transmission

The effects of acetylcholine, and of agents which selectively mimic or block its nicotinic and muscarinic actions, have been studied on the levels of guanosine 3,5-monophosphate (cyclic GMP) and adenosine 3,5-monophosphate (cyclic AMP) in slices of bovine superior cervical ganglion. Low doses of either acetylcholine or the muscarinic agonist, bethanechol, caused a substantial increase in the level of cyclic GMP, and slightly increased the level of cyclic AMP; the acetylcholine- and the bethanechol-induced increases in cyclic GMP were blocked by atropine, the muscarinic antagonist, but not by hexamethonium, the nicotinic antagonist. The nicotinic agonist N,N-dimethylphenylpiperazinium did not alter the level of either of the cyclic nucleotides. Dopamine increased the level of cyclic AMP and acetylcholine partially prevented this dopamine-induced increase in cyclic AMP. The data are consistent with a model for the ganglion in which muscarinic cholinergic synaptic transmission is mediated by an increase in the level of cyclic GMP in the postganglionic neurons and dopaminergic transmission by an increase in the level of cyclic AMP in these neurons.

Cyclic AMP and cyclic GMP: studies utilizing immunohistochemical techniques for the localization of the nucleotides in tissue

Antibodies to the cyclic nucleotides initially were utilized in radioimmunoassays for cyclic AMP and cyclic GMP which might be present in mammalian tissues. allowed measurement of the nucleotides on small amounts of tissue in physiologic studies. To gain further insight into the relative roles of cyclic AMP and cyclic GMP in cell function, these antibodies have been applied to immunohistochemical studies for the localization of the cyclic nucleotides in tissues and cells. This methodology is useful for determining in which cell type in a heterogeneous tissue increases in cyclic nucleotide concentrations occur. In addition, within individual cells, staining patterns for cyclic AMP and cyclic GMP are usually quite distinct. Cyclic GMP in canine thyroid is located to the follicular cell membrane while cyclic AMP is ubiquitously distributed in follicular cell cytoplasm. In both rat adrenal cortex and testis, there is prominent nuclear localization of cyclic GMP, suggesting a role for the nucleotide in growth regulation. These studies provide histologic evidence suggesting diverse roles for cyclic AMP and cyclic GMP in mammalian physiology. It is anticipated that this technique will also be useful in the ultrastructural localization of the cyclic nucleotides and for the identification of other cyclic nucleotides which might be present in mammalian tissues.